Bicycle transmissions that are configured as multi-speed gear hubs are known in the art in a variety of embodiments. Reference is presently being made to the specifications U.S. Pat. No. 3,432,013; DE 38 19 065 A1 (and the corresponding document GB 2 207 966 A); EP 0 383 350 A2; U.S. Pat. No. 3,608,683; as well as DE 41 42 867 A1.
EP 2 327 612 A2 discloses a multi-speed gear hub for bicycles that would correspond to a bicycle transmission of the type as mentioned below if a driver freewheeling clutch were implemented between a driver and an ring gear of a first gear level as a pawl freewheeling clutch, which is considered as particularly expedient in practice.
In a bicycle transmission of this kind, a ring part of the bicycle transmission is frequently allocated to the pawl, which is variable relative to the first component, and which interacts with the pawl such that in a first position of the ring part relative to the first component, which is referred to below as an activation position, the pawl is in the engagement position or at least biased in the direction of being in the engagement position; and that, based on an adjustment of the ring part from the activation position into a second position, which is referred to below as the deactivation position, the pawl is removable relative to the first component from the engagement position.
Correspondingly, U.S. Pat. No. 3,432,013 discloses in this sense a control sleeve as a third component that removes, during the brake action, two drive pawls against restoring forces of a spring from the engagement position, whereby now it is possible to transmit via the brake pawls torque to the brake means without the result of a strain on the transmission causing a so-called “brake lock” that must absolutely be avoided; the brake means herein is engaged and can no longer be disengaged because the forward pedaling action that is necessary for disengaging the brake means is prevented by the drive pawls that are in the engagement position and contact the allocated engagement formation. DE 38 19 065 A1 (and/or the corresponding GB 2 207 966 A), EP 0 383 350 A2 and DE 41 42 867 A1 disclose known prior-art configurations of this kind. Similarly U.S. Pat. No. 3,608,683 also specifies a relevant construction.
The prior art describes implementations of freewheeling and/or one-way clutches using roller elements that are clamped between an engagement surface of a first component and a cam surface of a second component in order to transmit torque, as implemented, for example, according to EP 0 679 970 B2.
DE 44 02 344 C1 discloses removing a pawl from an engagement position by means of a cam element against the force of a biased spring holding the pawl in the direction of the engagement position. In the known solution according to DE 44 02 344 C1, the pawl serves to couple a ring body to the hub axle in a non-rotatable manner; and the cam element releasing the pawl is constituted of a control slide that is coaxially displaceable relative to the hub axle.
Specification DE 42 29 023 C2 discloses a solution with two pawl sets that can be activated and deactivated interactively by means of an axially displaceable control disc, which holds the pawls of a first pawl set in a first axial position in the engagement position thereof and releases the pawls of a second pawl set from the engagement position, holding the pawls of the second pawl set in their engagement position, in a second axial position, allowing the removal of the pawls of the first pawl set from the engagement position thereof. The pawls, respectively, are biased by a pawl spring in the direction of a release position in which the pawls do not engage with an engagement formation allocated to them. Forces that are generated during the transmission of torque have an effect in the sense of a controlled removal of the pawls. The control disc is axially variable due to shifting forces, by means of sliding blocks introduced from the outside into the multi-speed hub in order to shift between at least two gears of the multi-speed hub by means of the aforementioned interactive activation and deactivation of the two pawl sets.
EP 2 112 062 A1 discloses the use of a so-called “negatively preloaded pawl” in a planetary gear mechanism of a bicycle transmission that is supported by a stationary carrier element serving for optionally releasing or, in the alternative, blocking a sun gear as well as providing a freewheeling function for the blocked sun gear. The spring-preloaded pawl can be shifted between two states by a cam element that is able to rotate across a small angle of rotation relative to the carrier element. In a first state, the pawl allows for any rotation of the sun gear relative to the carrier element, meaning rotation in both possible directions of rotation. In a second state, the pawl prevents the sun gear from turning in a first direction of rotation relative to the carrier part but allows a rotation of the sun gear in a second direction relative to the carrier part that is opposite to the first direction of rotation. To implement these functions, the pawl is pivotable, on the one hand, depending on the position of the cam element around a first pivot axis into a position corresponding to the first state, and, on the other hand, it is pivotable around a second pivot axis in order to implement a freewheeling function corresponding to the second state.